1. Technical Field
This invention relates generally to internal combustion engines, and more particularly to piston and connecting rod assemblies therefor.
2. Related Art
It is known that internal combustion engines have piston and connecting rod assemblies requiring use of a wrist pin for operable connection of a small end of the connecting rod to the piston. In particular, piston constructions are known to include a piston body with a pair of pin bosses depending from a crown of the body to a pair of axially aligned pin bores spaced laterally from one another. To transmit rotational motion to linear motion of the piston, a large end of a connecting rod is attached to a crank shaft of the engine and a small end of the connecting rod is received between the pin bosses for operable attachment to the piston via a wrist pin. To facilitate reducing friction between the wrist pin and the pin bores, it is known to insert journal bearings within the pin bores. Although these piston and connecting rod assemblies are widely accepted and useful, continual efforts are made to attain certain goals, for example, to reduce weight, to reduce envelope size, to improve manufacturing efficiencies and to reduce component costs.
Pistons are known that eliminate the need for a wrist pin connection between the connecting rod and the piston body. These piston constructions provide direct attachment of the piston body to the connecting rod. The piston has a single boss depending from the crown of the piston body with a single bore formed adjacent the end of the boss. A journal bearing is disposed within the bore and a slot depends from the bore with keyway formed through one sidewall of the boss. The connecting rod is constructed generally the same as in a conventional piston, with a shank extending to a small end. The small end, however, rather than providing a wrist pin bore, has an outer surface that extends laterally outwardly from sides of the shank to provide a cylindrical surface for receipt in the journal bearing. For assembly, the shank slides through the keyway in one sidewall of the boss while being obstructed by a wall at the opposite sidewall.
A piston constructed in accordance with this invention, while also eliminating the need for a wrist pin, provides further advancement in the attainment of the goals mentioned above, in addition to others that will be readily recognized by those skilled in the art of piston assemblies.